<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // saync await 是同步的
        async function async1() {
            console.log('async start');
            await async2();
            console.log('async1 end');
        }

        async function async2() {
            console.log('async2');   
        }

        async1();
        console.log('start');
    </script>
</body>
</html>